Code like ${!#} flags the "#" as shDerefWordError [1]; the "!prefix"
syntax region delegates to one of the shDerefSpecial handlers via
@shDerefList, but it misses the "#" case as valid for ${##} and ${!#}.
[1]: https://vi.stackexchange.com/q/48617/10604
Correct that. Indirection is only valid in Bash in Ksh, so rearrange the
"!" handling to be conditional.
closes: #20016
Helped-by: Christian Brabandt <cb@256bit.org>
Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
bash 5.3 (released July 2025) added support for ${ cmd;} and
${|cmd;} style command substitution, which is similar (but not
identical) to ksh/mksh.
closes: #18084
Signed-off-by: Kevin Pulo <kevin.pulo@mongodb.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>